The Scriptural case for obeying the Fourth Commandment is clearly and authoritatively set forth in the Old Testament. Since the New Testament was not canonized until the fourth century AD, the Church based its tradition of “remembering the Sabbath day and keeping it holy” on those Scriptures. It was the tradition of the church to keep the seventh day Sabbath and the Levitical Feasts until they were forbidden to do so by the pagan Roman Emperor Constantine in 325 AD.
Take a look at the following Scripture passages and ask yourself three questions. First, "How seriously does Yahveh take the 4th Commandment?" Secondly, "Why would Yahveh change His mind about something He felt so strongly about?" Thirdly, " Is there anything in Scripture to clearly suggest that He has changed His mind about the 4th Commandment, or that He wanted the Sabbath moved from the seventh day to the first day?"
Genesis 2:2-3; Exodus 20:8-11; Exodus 31:12-17; Exodus 35:2-3; Leviticus 23:1-3; Numbers 15:32-36;
Deuteronomy 5:12-15; Nehemiah 9:13-14' Isaiah 56:1-7; Isaiah 58:13-14; Matthew 5:17-20.